Cutting mechanism for thin, elongate structures



Oct. 15, 1968 w. EICHENBERGER 3,405,582

CUTTING MECHANISM FOR THIN, ELONGATE STRUCTURES Filed March 29, 1966 10 g \4 a \1 1 n K? ,-JT-A w W MMENTOE, Mam? 56 EN5565 7 6y L QM au United States Patent 3,405,582 CUTTING MECHANISM FOR THIN, ELONGATE STRUCTURES Werner Eichenberger, Zurich, Switzerland, assignor to Aktiengesellschaft Gebruder Loepfe, Zurich, Switzerland, a corporation of Switzerland Filed Mar. 29, 1966, Ser. No. 538,320 Claims priority, application Switzerland, Apr. 16, 1965, 4,748/ 65 Claims. (Cl. 83-568) ABSTRACT OF THE DISCLOSURE A quick-operating cutting device for yarns, wires and the like, especially for use in yarn cleaners, wherein the cutting device comprises a knife having a dull cutting edge, a flat movable countersurface for the knife and a quick-operating drive means for the flat movable countersurface. The knife is pivotally mounted such that the dull cutting edge faces the flat countersurface. The quickoperating drive means for the fiat countersurface preferably comprises an electromagnetic mechanism and serves to move the flat countersurface in a direction perpendicular to the surface thereof and towards the cutting edge of the knife. The knife, due to its pivotal mounting, adjusts itself upon contact with the countersurface to the momentary position of the countersurface thereby ensuring a proper cut and long life of the elements.

The present invention has reference to a new and improve-d cutting or severing mechanism for cutting thin, elongate structures by means of a cutting knife and a countersurface.

Such type cutting mechanisms are especially employed in textile machines for cutting a moving or stationary thread or yarn, for instance in a winding machine upon the occurrence of a yarn defect.

In addition, apparatuses have already become known to the art wherein the movement of the yarn with respect to a cutting edge is relied upon for implementing the cutting operation. In British Patent 716,370 disclosing such a known cutting device or mechanism, the yarn travels upon a flat surface perpendicular to the cutting edge of a rotatably mounted knife or cutter. To sever the yarn, the cutter is rocked towards such yarn, and contacts such at an angle with respect to the yarn. Since the yarn moves further the cutting edge penetrates or engages it more and more, Wearing it down until it is so thin that the resistance offered at the yarn by the cutting edge is greater than the breaking strength of the thus weakened yarn, the latter thereby finally rupturing. In this type apparatus it will be appreciated that the yarn essentially severs itself.

It should be apparent that such type severing or cutting device or mechanism cannot provide a short and clean or smooth cut. On the contrary, the severed ends of the yarn exhibit long, strongly frayed regions. Upon winding the yarn, the individual frays of the yarn end become embedded or clamped in different yarn layers, so that this yarn end can no longer be seized by the nowadays conventional automatic pneumatic yarn finders.

A further considerable disadvantage is that the known cutting device is not suitable for smooth synthetic yarn materials, The synthetic yarn materials possess such a smooth surface that the latter is not engaged or pierced by the cutting edge and the yarn can move beneath such without being acted upon.

Finally, with the above-described cutting device, it is not possible to sever a yarn or other structure which is at standstill. This requirement is, however, of basic importance for yarn monitors or supervising mechanisms 3,405,582 Patented Oct. 15, 1968 used in textile machines and the like. For example, if a yarn which has been knotted after a control operation and again inserted in the control apparatus, still exhibits a defect or fault, a double thread for instance, then the cutting mechanism must respond and sever the yarn before the machine is placed into operation. However, this requirement cannot be fulfilled with the known device.

According to another known cutting device or mechanism, disclosed in Swiss Patent 374,349, working according to the principle of the scissors, the above disadvantages are partially remedied. However, this apparatus, on the other hand, possesses new defects. Both scissor blades must be manufactured and installed with great precision. The air gap between the blades must be of very small size, otherwise it is impossible to ensure for faultless cutting, particularly in the case of fine yarns. Moreover, the rubbing of the scissor blades upon one another results in increased wear. Such type cutting mechanism therefore requires continual supervision and in consideration of constant operational reliability must be frequently exchanged and overhauled.

Accordingly, it is a primary object of the present invention to provide an improved cutting or severing mechanism for thin, elongate structures which effectively overcomes the aforementioned disadvantages of the prior art devices, is robust, also highly reliable in operation.

Another, more specific and noteworthy object of this invention is directed to the provision of a new and improved cutting mechanism for the faultless cutting of thin, elongate structures, especially fine as well as coarse threads, yarns or the like, formed of synthetic or natural material, and irrespective whether such are moving or at standstill.

Still a further important object of this invention pertains to the provision of an improved cutting mechanism for reliably and effectively cutting filamentous material, does not require a great deal of supervision, is robust in construction, positive in operation.

In order to implement these and still further objects of the invention which will become more readily apparent as the description proceeds, the inventive cutting mechanism for the cutting or severing of thin, elongate structures incorporates a cutting knife and a countersurface, the cutting knife possessing a blunt cutting end portion, and the cutting knife and countersurface are formed of hard metal. The inventive cutting mechanism is particularly useful for cutting yarn or other filamentous material in textile machines.

According to one inventive aspect of the cutting mechanism, the cutting knife and/or the countersurface are movable relative to one another in a plane perpendicular to the countersurface. Such arrangement enables the best possible utilization of the energy of the displaceable component for carrying out an active cutting operation, meaning a cutting operation providing a short clean cut essentially crosswise of the thickness of the yarn or other structure, as opposed to a cutting operation which tears the material somewhat diagonally along its length.

According to the invention, the cutting knife and the countersurface are formed of such a hard material that upon impact of knife and countersurface, no permanent plastic deformation occurs. Therefore, there is obtained both longevity of the employed components and always an exact and clean parting or separation of the elongate structure to be cut.

According to a further aspect of the invention, the cutting knife of the inventive cutting mechanism is constructed as an oscillatory or pivotably mounted anvil, in other words, is a stationary component. It is therefore not necessary to manufacture and adjust the displaced components of the apparatus with any great precision, since the cutting knife can easily adjust itself to the momentary position of the countersurface. A particularly advantageous physical construction of inventive cutting mechanism resides in moving the countersurface by means of a magnet, and the countersurface is arranged in such a manner that it is directly connected with the extension of the elongated armature of the magnet such that magnet, armature and countersupport are coaxially aligned. Due to this construction and arrangement of the drive for the countersurface, it is possible to make maximum use and transmission of the magnetic force.

The inventive cutting mechanism or apparatus is particularly suitable for cutting or severing thin, elongate structures of the most varied types, such as for instance threads, yarns, or filaments, of synthetic or natural materials, or thin wires. A preferred application of the inventive cutting mechanism is for separation or cutting of yarns or the like in textile machines.

Other features, objects and advantages of the invention will become apparent by reference to the following detailed description and drawing in which:

FIGURE 1 is a longitudinal sectional view of a first embodiment of inventive cutting mechanism utilizing an electromagnet wherein the countersurface is moved thereby and is coaxially arranged with regard to the magnet coil;

FIGURE 2 is a top plan view of the cutting mechanism depicted in FIGURE 1;

FIGURE 3 is a longitudinal sectional view, similar to FIGURE 1, but here showing a modified construction wherein the drive of the countersurface takes place via a rod arrangement;

FIGURE 4 is an enlarged, fragmentary view of the knife cutting portion having cutting faces ground at an angle of 90 with respect to one another;

FIGURE 5 is an enlarged, fragmentary view of a further form of cutting knife having main facets or bevelled faces ground at an angle of 90 to one another and actual cutting faces ground at an angle greater than 90; and

FIGURE 6 is a diagram of an electrical circuit for operating either the cutting mechanism of FIGURE 1 or 3.

Describing now the drawing, FIGURE 1 depicts an exemplary embodiment of inventive cutting mechanism or apparatus embodying a cutter or knife 1 and a countersurface 2. This knife 1 is advantageously constructed as an anvil, i.e. does not carry out any linear displacement, yet is preferably mounted for rocking or oscillatory movement by a pin 3 at a support 4. A stop or limit memher 5 retains the knife 1 in a slightly inclined position with respect to the countersurface 2. This countersurface 2 for the cutter or knife 1 consists of a small plate fixedly connected with a carrier or support 6 of circular metallic material. Carrier or support 6 is retained in a guide insert or member 7 coaxially with respect to the coil 8a of an electromagnet 8 and is provided at its end opposite the countersurface 2 with a piston 9 constructed as an armature for such electromagnet. This piston or armature 9 is located essentially outside of the region of the coil 8a when it is in its rest position.

Carrier or suport 6 which, in effect, is an extension of the armature 9, and the guide insert 7, are constructed such that an axial displacement of this armature or piston 9 through the distance X in the direction of the coil 8a is possible whenever this coil has current supplied to it by the conductors or leads 10 (FIGURE 2) and thereby attracts such armature 9. Spring 11 returns the armature 9, thereby also the countersurface 2, back into its starting position when no current is flowing through the coil 8a of the magnet 8.

Carrier 6, guide insert 7 and coil 8a are arranged in a housing 12 which, like the support 4 for the knife or cutter 1, is secured to a base plate 13. In order to protect the drive components from dust or contamination by other foreign material, sealing member 14 is arranged between the guide insert 7 and the carrier or support 6 and which is preferably a rubber jacket or covering. By referring to the plan view of the above-described embodiment of cutting device depicted in FIGURE 2, it will be recognized that a yarn 15 for instance, is retained in proper position at the cutting mechanism by the guide elements 16.

According to the variant construction of cutting mechanism depicted in FIGURE 3, the carrier or support 6, together with the counter-surface 2, can also be located externally of the coil 8a of the magnet 8. In this instance, the carrier -6' is guided in the support members 17 and receives its driving force via a tiltable or rockable lever 19 operatively associated with the electromagnet 18 having a coil 8a. A spring 11 acting upon an impact member 20 arranged at the carrier 6' returns the aforesaid carrier 6' carrying the countersurface 2 always back into the starting position. The drive components for the cutting mechanism of FIGURE 3 are also arranged in a housing 12 and protected against contamination by dust or otherwise, by a seal means 14' preferably formed as a rubber jacket or casing. The further physical construction of this embodiment of separating or cutting mechanism corresponds exactly to that previously described with respect to FIGURES l and 2.

FIGURES 4 and 5 depict different embodiments, in enlarged scale, of the cutter or knife unit. Generally, a cutter or knife 1 of the construction depicted in FIG- URE 4 is employed and whose cutter end 10 has cutting surfaces or faces 21 and 22 ground at an angle of preferably with respect to one another. However, it is to be understood that the cutter portion 1a, of the knife could be made blunter, as such is shown by the cutter 1' of FIGURE 5. Here at the cutter end portion 1a only the main facets or bevelled faces 23- and 24 are at an angle of 90 with respect to one another, whereas the actual cutting flanks or faces 21 and 22 enclose an angle greater than 90. The blunter the cutting portion, the less its deformation and therefore its wear. Therefore, the cutter or knife of the inventive cutter mechanism has a blunt cutter end portion which can even have slightly rounded or curved cutting faces, and wherein the cutting faces enclose an angle with respect to one another of at least 45, and preferably at least 90.

One of the major advantages of the described inventive cutting mechanisms resides in their simple construction and extremely simple operation. A cutting operation is initiated by a current surge, for instance delivered by a control device. This current surge produces an electromagnetic field in the coil 8a which attracts either the armature 9 or the tiltable lever 19, so that it carries out a jerky or rapid movement. Consequently, the countersurface 2 moves against the cutter or knife 1 or 1' and severs the structure lying between these elements. The oscillatory or rockable mounting of this knife or cutter 1 or 1, as previously explained, ensures that in each instance the aforesaid knife and countersurface 2 compactly abut against one another. Therefore, the inventive cutting mechanism performs an active cutting operation resulting in an actual clean cut in contrast to the known device described at the outset of this disclosure.

In order to ensure for faultless operation and long life of the cutting mechanism, it is necessary to observe certain particularities or characteristics. First of all, it is important that cutter and countersurface are formed of very hard and tough material, as such are known to the art, e.g. hard steel, so that upon impacting one another the occurring deformation in each case is reversible, that is to say, takes place in the elastic range of the material. Consequently, it is possible to obtain a practically unlimited longevity of knife and countersurface.

If the cutting mechanism is employed for the severing of travelling yarns, threads, and so forth, then it is necessary that the knife and countersurface possess a width (measured along the plane of the drawing of FIGURES 1 and 3) which is a multiple of the diameter of such thread or the like. In any case, the width of the cutting edge and countersurface must be so large that the cutting mechanism can faultlessly engage the thread or yarn even then if such goes into transverse oscillations during passage through the cutting mechanism. In accordance with a practical manifestation of the invention, cutter and counter-surface were each made one centimeter wide.

To achieve faultless cutting of yarn, thread and so forth, it is furthermore necessary that impact of the countersurface against the cutter or knife take place with an appropriately high kinetic energy in order to bring about destruction of the fibrils of the yarn or thread. In any event, it has been found that the kinetic energy should not be obtained only through high velocity of the moved component. With small mass of the countersurface the danger exists that the recoil Will be too large and knife and countersurface will go into oscillation, whereby faultless separation is endangered. In designing the inventive cutting mechanism, the driving force and the mass of the moved body must be in such a relationship to one another that the impact of countersurface and cutter occurs approximately aperiodic.

The circuit depicted in FIGURE 6 has been found particularly advantageous for obtaining the relatively high energy, which is only required for short periods of time, from conventionally employed low-voltage current. By inspecting such figure there will be seen that the circuit contains a transformer 25 which steps down the network voltage and delivers such to a full-wave rectifier 26. This rectifier 26 feeds a storage capacitor 28 via a charging resistor 27. Parallel to the capacitor 28' there is coupled the series arrangement of the winding or coil of the electromagnets 8 and 18 of FIGURES 1 and 3 and a work contact 34 which is actuated by a relay 29, i nturn controlled via a suitable transistor 30.

If, for example, a short duration control pulse 31 of two volts and sixty miliseconds duration arives from a yarn-supervising mechanism or monitoring device of a textile machine at the control transistor 30, then the latter becomes conductive for the corresponding short period of time, the relay 29 responds, and the current circuit is closed for the duration of such control pulse. Consequently, the storage capacitor 28 discharges and acts upon the electromagnet 8 or 18. In order to extinguish sparks at the contact 34 of the relay 29 there is coupled in parallel with such contact a series arrangement of resistor 32 and capacitor 33. Due to the described circuit there is only required about one-twentieth of the power of the lowvoltage current network in contrast to a direct connection.

It is further indicated that the cutting mechanisms described in accordance with the previous exemplary embodiments are particularly suitable for cutting or severing thread, yarn or the like, irrespective whether natural or synthetic material is employed. Experiments or trials have shown that it is possible to cut the finest yarns of Nm. 300 up to the coarsest of Nm. 2 faultlessly, either when such are stationary or moving. Long frayed ends of the yarn are prevented due to the exceptionally small cutting time which, on the average, amounts to 0.1 to 0.2 millisecond. Although the drive of the cutting mechanism in the previous examples has been described as taking place by means of an electromagnet, it is to be clearly understood that this does not exclude the use of a different type of drive, for instance that the drive is effectively also undertaken by means of a piston impacted by compressed air or other pressurized fluid medium.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A quick-operating cutting device for yarns, wires and the like, said cutting device being capable of being used in yarn cleaners, said cutting device comprising:

a knife having a blunt cutting end portion;

a flat countersurface for said knife;

a quick-operating drive means for said fiat countersurface;

means for pivotally mounting said knife with the cutting end portion thereof facing said flat countersurface; said drive means for said flat countersurface moving said countersurface in a direction perpendicular to said surface and towards said cutting end portion of said knife; whereby said knife due to said pivotal mounting thereof adjusts itself upon contact with said countersurface to the momentary position of said countersurface.

2. Cutting mechanism for cutting thin elongate structures as defined in claim 1, wherein said blunt cutting end portion has face portions enclosing an angle with one another of at least 45.

3. Cutting mechanism for cutting thin elongate structures as defined in claim 1, wherein said blunt cutting end portion has face portions enclosing an angle with one another of about 4. Cutting mechanism for cutting thin elongate structures as defined in claim 1, wherein said blunt cutting end portion has a pair of face portions enclosing an angle with one another of 90 and a further pair of face portions providing the actual cutting edge which enclose an angle with one another which is greater than 90.

5. Cutting mechanism for cutting thin, elongate structures, said cutting mechanism comprising a cutting knife and a countersurface, said cutting knife possessing a blunt cutting end portion, said cutting knife and said countersurface being formed of hard metal, means for displacing said countersurface relative to said cutting knife in a plane substantially perpendicular to said countersurface, and wherein said displacing means comprises an electromagnet provided with an armature.

6. Cutting mechanism for cutting thin elongate structures as defined in claim 5, wherein said armature is provided with an extension to which there is directly connected said countersurface.

7. Cutting mechanism for cutting thin elongate structures as defined in claim 5, wherein said armature and said countersurface are coaxially arranged.

8. Cutting mechanism for cutting thin elongate structures as defined in claim 5, further including sealing means arranged between said countersurface and said electromagnet.

9. Cutting mechanism for cutting thin elongate structures as defined in claim 5, said electromagnet having a coil, circuit means for controlling energization of said coil, said circuit means including a relay in circuit with said coil, a control transistor for controlling operation of said relay, a storage capacitor connected in parallel with said relay, a direct-current source, and a charging resistor coupling said storage capacitor with said direct-current source.

10. Cutting mechanism for cutting thin elongate structures as defined in claim 1, wherein said blunt cutting end portion of said cutting knife has a width which is a multiple of the diameter of the structure to be cut.

References Cited UNITED STATES PATENTS 2,361,288 '10/1944 Hardy 83679 X 3,023,656 3/1962 Glastra 83-577 3,176,572 4/1965 Comet 83-679 X 3,322,013 5/1967 Felix 83588 X WILLIAM S. LAWSON, Primary Examiner. 

